/**
 * 加载js
 * @param url
 * @param attr 属性
 */
export function loadScript(
    url: string,
    attr?: { [key: string]: string }
): Promise<any> {
    return new Promise((resolve, reject) => {
        if (
            (document.scripts as any).some(
                (script: HTMLScriptElement) => script.src === url
            )
        ) {
            resolve();
        } else {
            const script = document.createElement("script");
            if (attr) {
                for (const key in attr) {
                    script.setAttribute(key, attr[key]);
                }
            }
            script.type = "text/javascript";
            script.src = url;
            script.onload = resolve;
            script.onerror = reject;
            document.body.appendChild(script);
        }
    });
}